1. Field of the Invention
The present invention relates generally to components and accessories for reciprocating internal combustion engines, and more particularly to a plate for installation across the main bearing caps of such an engine, and serving to tie the caps more rigidly together to increase the strength and rigidity of the engine block. The present reinforcement plate is particularly adapted for installation on a General Motors LS-1 engine of approximately 5.7 liters displacement, but may be adapted (with dimensional modifications as required) to virtually any reciprocating internal combustion engine.
2. Description of the Related Art
The internal combustion engine has been known since the latter part of the nineteenth century, and has seen continuous revisions and refinements over the years. Initially, such engines produced relatively little power for their size and weight, with metal fatigue due to flexing and stress being of little concern, even with the relatively weak metals available at the time.
However, as reciprocating engine technology was refined over the decades, the additional power output of such engines resulted in a need for greater consideration of the internal stresses imposed upon such an engine due to the power impulses developed during operation. Accordingly, advanced metallurgy has resulted in stronger metals for use in casting, forging, and machining of the various components used in such engines, and better engineering and manufacturing technology have resulted in more efficient castings, forgings, and machined parts for such engines. However, engines in mass production have certain constraints regarding the economics of manufacture, and many such engines may be improved structurally through the installation and use of various aftermarket components which the manufacturer deems to be economically unfeasible at the time of manufacture.
This is particularly true in the case of relatively high performance engines, which have relatively high power output for their size and weight. A case in point is the General Motors LS1 V-8, which has on the order of 5.7 liters or 350 cubic inches of displacement. This is a so-called “small block” V-8, which has been developed over multiple generations from an earlier, cast iron block V-8 having a displacement of only about 4.3 liters, or 283 cubic inches. Further development of this engine has resulted in relatively lightweight aluminum blocks having considerably greater displacement (depending upon the crankshaft stroke) than the original engine, and thus being capable of developing considerably more power. In addition, improvements in fuel antiknock qualities, as well as fuel injection, electronic ignition, and other refinements, have resulted in an engine in its stock form which is capable of developing well over twice the power of the original engine, and considerably more than that when modified. The additional power developed results in proportionally greater internal stresses in the engine during operation, with even such apparently rigid components as the engine block actually twisting and moving during engine operation. While such movement is extremely small, on the order of a few to perhaps several thousandths of an inch, the rapid flexing which occurs results in fatigue stress of the engine block and other components, which over some period of time can lead to engine damage and failure.
While these stresses and movements exist in stock engines as well as in modified engines, engineers working with stock engines have developed such engines to the point that they are quite reliable, with engine blocks and other major components typically lasting for well over one hundred thousand miles without failure. However, engines which have been modified for greater power are a different matter. The stresses developed by the greater power output of such modified engines can often result in engine damage in a relatively short period of time. This may be acceptable to those involved in racing events, and who are willing to rebuild their engine(s) relatively frequently. There is another consideration, however, and that is that the twisting and other movement of components leads to the slight misalignment of components, and correspondingly greater frictional wear of bearings and other components within the engine.
The present invention responds to these problems by providing a flat, planar reinforcement plate configured for attachment across the main bearing caps of a reciprocating internal combustion engine, thereby serving to tie the bearing caps more rigidly together and to greatly reduce relative movement between the main bearings in the engine. This reduction of relative movement between bearing caps thus greatly improves the alignment of the bearings during engine operation, thereby greatly reducing bearing friction and improving operational efficiency of the engine. Moreover, as the bearing caps are bolted to the block and the present reinforcement plate is bolted across the bearing caps to tie them rigidly together, movement of the engine block is constrained, thereby reducing fatigue stresses in the block. While the present reinforcement plate is adaptable to virtually any reciprocating internal combustion engine, it is particularly well suited for installation in General Motors LS-1 V-8 engines having aluminum engine blocks, and even more particularly in such engines which have been modified to produce a greater power output than stock.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 3,046,954 issued on Jul. 31, 1962 to Carl S. Hoffman et al., titled “Crankcase And Bearing Structure For Internal Combustion Engines,” describes numerous embodiments of engine main bearing reinforcements. Most of the embodiments comprise multiple component links stamped of relatively thin metal which tie only two adjacent bearing caps together along one side of the engine, rather than spanning all of the main bearing caps to interconnect all of the caps, as in the present invention. In one embodiment of Hoffman et al., an elongate stamped component is secured to the main bearing caps along each side of the engine, but this still requires two separate and non-interconnected components, rather than the single, unitary, monolithic reinforcement plate of the present invention. In another Hoffman et al. embodiment, a single plate is provided which is bolted to all of the main bearing caps directly beneath the crankshaft, but this single plate does not use the main bearing cap bolts to anchor it to the bearing caps. Rather, a series of smaller bolts are used to bolt the continuous plate to the bearing caps, thus obviating much of the advantage of spanning the bearing caps with a single, unitary plate. Moreover, none of the embodiments of the Hoffman et al. reinforcements extend the entire length of the multiple bearing cap assembly and also span the entire internal width of the crankcase at the lower surface of the bearing caps, as does the present reinforcement plate.
U.S. Pat. No. 3,841,203 issued on Oct. 15, 1974 to Glenister S. Bruce, titled “Reciprocating-Piston Engines And Compressors,” describes a relatively thick plate formed by casting or forging, which is bolted to the bottoms of the main bearing caps of an engine or compressor. While Bruce illustrates an engine having four bolt main bearings, i.e. two bolts secure each of the bearing caps to the upper bearing support along each side thereof, for a total of four bolts per bearing and cap, he utilizes only the two outermost bolts to secure his plate to the bearing caps, rather than using all of the lower cap bolts for greater strength, as in the present invention. Moreover, Bruce requires some modification to the engine in order to install his reinforcement, at least in the form of longer outboard bearing cap bolts to accommodate the thickness of his plate. The present invention has been configured so as to avoid any requirement for modification to the engine or to require the substitution of any parts during the installation.
U.S. Pat. No. 4,219,002 issued on Aug. 26, 1980 to Hermann Danckert et al., titled “Sound Insulated Internal Combustion Engine,” describes the installation of a surrounding jacket or shell for such an engine to reduce the sound output from the engine itself. The assembly includes a “carrier ring” which is bolted to the bottom of the block, with the shroud attachment flange installed beneath the ring and the oil pan finally installed beneath the shroud. The entire assembly is separated from the engine block by a thick, relatively soft and resilient sound dampening gasket or the like, which does not allow any resistance to flexing and movement to be transmitted from the carrier ring and/or shroud attachment flange to the engine block. It is also noted that the components of the Danckert et al. sound insulation assembly do not attach to the bearing caps of the engine, and thus do nothing to maintain the relative rigidity and alignment of the bearing caps.
U.S. Pat. No. 4,465,041 issued on Aug. 14, 1984 to Yoshimasa Hayashi, titled “Cylinder Block Of Internal Combustion Engine,” describes the integral installation of a ferrous metal reinforcement in the lower portion of a light metal alloy (aluminum, etc.) engine block. While Hayashi describes the use of ferrous metal, the metals he describes are relatively low strength, i.e. cast iron or mild steel. Also, the Hayashi reinforcement must be accomplished at the time the engine block is cast, as the Hayashi reinforcement forms an integral part of the block. Moreover, as the Hayashi reinforcement is integrated with the block, it cannot serve to tie the main bearing caps of the engine together, as the caps are bolted to the block during engine assembly after the block has been cast and machined.
U.S. Pat. No. 4,656,983 issued on Apr. 14, 1987 to Nobuo Anno, titled “Crankshaft Supporting And Lubricating Structure For Multicylinder Internal Combustion Engines,” describes the installation of a “bridge” formed as a relatively complex casting and having a series of oil passages therein, for attachment across the main bearing caps of an engine. The Anno device requires modification of the engine, in that the bearing caps must be drilled to provide oil passages which communicate with the bridge when it is installed. The present invention is not directed to improving the lubrication of the engine, other than by maintaining more precise alignment of the main bearings by means of the increased engine block and bearing cap rigidity provided by its installation.
U.S. Pat. No. 4,771,747 and Reissue No. 33,575 issued respectively on Sep. 20, 1988 and Apr. 23, 1991 to Benny Ballheimer et al., titled “Internal Combustion Engine Noise Reduction Plate,” both describe a plate which attaches across the lower portion of the block. In each embodiment, the Ballheimer et al. plate bolts to the lower edge of the block, to a flange extending inwardly from the skirt edge. The oil pan is bolted to another, externally extending flange coplanar with the inward flange. This block construction is unconventional for Otto cycle (four stroke cycle) internal combustion engines, and accordingly, the present reinforcement plate does not attach directly to the engine block itself. Rather, the present reinforcement plate bolts across all of the main bearing caps of the engine, to tie the caps rigidly together. The Ballheimer et al. plate does not attach or contact the main bearing caps of the engine.
U.S. Pat. No. 4,831,978 issued on May 23, 1989 to Isamu Iguchi et al., titled “Internal Combustion Engine Having Reinforced Structure,” describes another reinforcement plate which bolts to the lower edge of the skirt of the engine block, rather than bolting to the main bearing caps, as in the present reinforcement plate. The reinforcement plate of Iguchi et al. is a three dimensional, cast structure of relatively complex configuration in comparison to the present flat, planar reinforcement plate, and thus more closely resembles the reinforcement plate of the Bruce '203 U.S. patent discussed further above, than it does the present invention. No provision for attachment to the main bearing caps is provided by Iguchi.
U.S. Pat. No. 4,876,998 issued on Oct. 31, 1989 to Peter Wunsche, titled “Crankcase For Internal Combustion Engines,” describes a specially formed engine block and oil pan, with the pan including longitudinal stiffeners therealong. The pan is bolted to the bottom of the block in an inwardly extending bolt pattern, as opposed to the conventional peripheral pattern normally used. While the Wunsche oil pan may provide additional stiffness for the engine block, it does not attach to the main bearing caps of the engine, as does the present reinforcement plate.
U.S. Pat. No. 4,911,117 issued on Mar. 27, 1990 to Kazuaki Nishimura et al., titled “Arrangements For Supporting Crankshafts In Multicylinder Engines,” describes different embodiments of a brace which bolts to the main bearing caps of the engine and spans each main bearing with an arched connecting component. Additional bolts pass laterally through the device. The Nishimura et al. brace comprises a relatively complex, three dimensional casting or forging in comparison to the flat plate of the present reinforcement device, and the arched components between each of the bearing caps cannot provide the rigidity in tension and compression which is provided by the rigid, flat plate of the present reinforcement device. Moreover, the Nishimura et al. device is relatively narrow, and does not span the entire crankcase from side to side for the length of the crankcase, as provided by the present invention. The Nishimura device is adapted for use only with relatively low power engines having only two bolts per main bearing cap.
U.S. Pat. No. 5,009,205 issued on Apr. 23, 1991 to Ryoji Abe et al., titled “Crankshaft Supporting Structure For An Internal Combustion Engine,” describes different embodiments of a combination oil pan and reinforcement plate. The device comprises a relatively complex, three dimensional component which must be cast or forged, rather than the flat plate of the present invention. The engine of the Abe et al. reinforcement must be specially modified and configured to provide for the installation of their reinforcement device. Moreover, the bearing caps of the engine must be specially configured as well, to have downwardly extended, opposed ears or lugs to which the reinforcement plate attaches. The Abe et al. reinforcement device is not adaptable as an aftermarket component which may be quickly and easily installed in the field on an existing engine with no modification being required to that existing engine, as is the case with the present reinforcement plate invention.
U.S. Pat. No. 5,501,529 issued on Mar. 26, 1996 to Terry M. Cadle et al., titled “Bearing Support Insert,” describes an engine construction in which the upper portion of the main bearing housing, i.e. that portion which comprises a permanent component of the engine block, is integrally cast with the block at the time of engine manufacture. A conventional main bearing cap is bolted to the insert to hold the crankshaft in place after the engine has been machined and assembled. While this may provide a somewhat stronger lower end for the engine, there is no provision by Cadle et al. for a reinforcement plate which may be installed without modification to an existing engine.
U.S. Pat. No. 6,374,794 issued on Apr. 23, 2002 to Jean-Pierre Dudemaine, titled “Power Unit Including An Oil Pan Separation Piece,” describes a relatively thick, three dimensional component having a series of bolt passages extending longitudinally from, one end thereof with a series of mounting holes passing therethrough. The device is bolted to the bottom of the block along with the oil pan, with the device sandwiched between the skirt of the block and the oil pan attachment flange; no main bearing cap attachment is provided. The longitudinal bolt holes provide additional attachment of the engine block to the transmission, which is the main point of the Dudemaine component. A potential problem of such relatively thick components attached to the bottom of the engine, is the lowering of the oil pan to a point where it may interfere with vehicle structural members and/or contact the underlying surface. The thin configuration of the present plate poses no such hazards.
Japanese Patent Publication No. 61-294,160, published on Dec. 24, 1986, describes (according to the drawings and English abstract) a pair of embodiments for a reinforcement plate installed across the main bearing caps and lower skirt of the engine block. The Yanmar Diesel reinforcement plate resembles the plate of the Abe et al. '205 U.S. patent discussed immediately above, more closely than it does the present invention. The complex casting or forging and the relatively great thickness of the Yanmar Diesel plate result in greater expense, more complex installation, and possible interference with other structures.
Japanese Patent Publication No. 63-253,158, published on Oct. 20, 1988, describes (according to the drawings and English abstract) a complex stamped sheet metal plate with multiple ribs and other reinforcing components. The device secures to the engine block between the edge of the skirt and the oil pan, as well as to the main bearing caps. Sealing the device around the skirt and oil pan appears to be of some concern in the Mazda Japanese Patent Publication, as multiple gaskets are used with various butt and tongue and groove joints therebetween. As the present reinforcing plate does not extend between the edges of the engine block skirt and oil pan, no additional sealing is needed other than the stock oil pan gasket.
Finally, Japanese Patent Publication No. 9-264,187, published on Oct. 7, 1997, describes (According to the drawings and English abstract) another plate formed of numerous thin sheet metal parts. The plate of the '187 Japanese Patent Publication also attaches between the skirt of the engine block and the oil pan and to the main bearing caps, but uses a series of smaller, secondary bolts to secure to the caps rather than using the bearing cap bolts themselves. Moreover, the '187 plate attaches only to the second and fourth bearing caps in the four cylinder inline engine, rather than attaching to all five of the caps, as in the present reinforcement plate.
None of the above inventions and patents, either singly or in combination, is seen to describe the instant invention as claimed. Thus a reinforcement plate for a reciprocating engine solving the aforementioned problems is desired.